Manatees or sea cows as they are often called are large rotund marine animals that can weigh as much as 1,000 pounds. But despite their enormous size, the mostly herbivorous animals have no blubber to protect them from chilly winter waters. Hence, every winter, the gentle giants seek out warmer waters. For the approximately 6,000 Florida manatees that reside in the Gulf of Mexico it means heading to the balmy 72°F waters of the roughly one-acre Three Sisters Spring in Florida's Crystal River National Wildlife Refuge.